Ni–Fe Nanoparticles Embedded in N‑Doped\nCarbon for Broadband Microwave Absorption

Abstract

With\nthe advent of the 5G era, there has been increasing concern\nregarding the potential harm of electromagnetic wave radiation on\nhuman life. Consequently, the development of a simple and cost-effective\nbroadband and high-performance microwave absorber becomes crucial.\nIn this study, porous tremella like nanomaterials embedded with Ni–Fe\nnanoparticles in N-doped carbon were prepared by a simple salt template\nmethod. Given that carbon materials inherently lack magnetic loss\ndue to their own dielectric loss, in order to enhance microwave absorption\ncapacity, FeNi bimetal is added to introduce magnetic loss to achieve\nelectromagnetic synergy. By changing the pyrolysis temperature, adding\nNaCl and urea, the morphology of the material can be adjusted, the\nelectromagnetic parameters can be changed, and the impedance matching\ncan be adjusted to improve the microwave absorption performance. At\na 7.5% filling ratio of the synthesized FeNi/N–PCN(800) composite,\nthe minimum reflection loss (RL_min) is −46.4 dB,\nwith a mere 2 mm matching thickness. The effective absorption bandwidth\nextends up to 5.04 GHz, demonstrating successful broadband microwave\nabsorption. The radar cross section further proves that the material\nhas good microwave absorption characteristics in practical applications.\nThis work offers a reliable idea for subsequent studies on broadband\nand high-performance microwave absorbing materials.